我参考AN3126 用DAC产生一个20HZ的正弦波,但频率不稳定

xiaolin88

芯片是STM32F103VC
采样点是1305,DAC_OUT1产生正弦波20HZ.为什么产生的频率不稳定?请高手指点.谢谢!以下是我的编程,
#include "stm32f10x.h"

#define DAC_DHR12RD_Address      0x40007420

DAC_InitTypeDef            DAC_InitStructure;
DMA_InitTypeDef            DMA_InitStructure;
TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;
const uint16_t Sine12bit[1305] = {
2048 ,2058 ,2068 ,2078 ,2087 ,2097 ,2107 ,2117 ,2127 ,2137 ,2147 ,2156 ,2166 ,2176 ,2186 ,2196 ,
2206 ,2215 ,2225 ,2235 ,2245 ,2255 ,2265 ,2274 ,2284 ,2294 ,2304 ,2313 ,2323 ,2333 ,2343 ,2353 ,
2362 ,2372 ,2382 ,2391 ,2401 ,2411 ,2421 ,2430 ,2440 ,2450 ,2459 ,2469 ,2479 ,2488 ,2498 ,2507 ,
2517 ,2527 ,2536 ,2546 ,2555 ,2565 ,2574 ,2584 ,2594 ,2603 ,2613 ,2622 ,2631 ,2641 ,2650 ,2660 ,
2669 ,2679 ,2688 ,2697 ,2707 ,2716 ,2725 ,2735 ,2744 ,2753 ,2762 ,2772 ,2781 ,2790 ,2799 ,2808 ,
2817 ,2827 ,2836 ,2845 ,2854 ,2863 ,2872 ,2881 ,2890 ,2899 ,2908 ,2917 ,2926 ,2935 ,2944 ,2952 ,
2961 ,2970 ,2979 ,2988 ,2996 ,3005 ,3014 ,3023 ,3031 ,3040 ,3048 ,3057 ,3066 ,3074 ,3083 ,3091 ,
3100 ,3108 ,3116 ,3125 ,3133 ,3142 ,3150 ,3158 ,3167 ,3175 ,3183 ,3191 ,3199 ,3207 ,3216 ,3224 ,
3232 ,3240 ,3248 ,3256 ,3264 ,3272 ,3280 ,3287 ,3295 ,3303 ,3311 ,3319 ,3326 ,3334 ,3342 ,3349 ,
3357 ,3364 ,3372 ,3379 ,3387 ,3394 ,3402 ,3409 ,3417 ,3424 ,3431 ,3438 ,3446 ,3453 ,3460 ,3467 ,
3474 ,3481 ,3488 ,3495 ,3502 ,3509 ,3516 ,3523 ,3530 ,3537 ,3543 ,3550 ,3557 ,3563 ,3570 ,3577 ,
3583 ,3590 ,3596 ,3603 ,3609 ,3615 ,3622 ,3628 ,3634 ,3640 ,3647 ,3653 ,3659 ,3665 ,3671 ,3677 ,
3683 ,3689 ,3695 ,3701 ,3706 ,3712 ,3718 ,3723 ,3729 ,3735 ,3740 ,3746 ,3751 ,3757 ,3762 ,3768 ,
3773 ,3778 ,3783 ,3789 ,3794 ,3799 ,3804 ,3809 ,3814 ,3819 ,3824 ,3829 ,3834 ,3839 ,3843 ,3848 ,
3853 ,3857 ,3862 ,3867 ,3871 ,3876 ,3880 ,3884 ,3889 ,3893 ,3897 ,3902 ,3906 ,3910 ,3914 ,3918 ,
3922 ,3926 ,3930 ,3934 ,3937 ,3941 ,3945 ,3949 ,3952 ,3956 ,3960 ,3963 ,3967 ,3970 ,3973 ,3977 ,
3980 ,3983 ,3986 ,3990 ,3993 ,3996 ,3999 ,4002 ,4005 ,4008 ,4010 ,4013 ,4016 ,4019 ,4021 ,4024 ,
4027 ,4029 ,4032 ,4034 ,4036 ,4039 ,4041 ,4043 ,4045 ,4048 ,4050 ,4052 ,4054 ,4056 ,4058 ,4060 ,
4061 ,4063 ,4065 ,4067 ,4068 ,4070 ,4071 ,4073 ,4074 ,4076 ,4077 ,4078 ,4080 ,4081 ,4082 ,4083 ,
4084 ,4085 ,4086 ,4087 ,4088 ,4089 ,4090 ,4090 ,4091 ,4092 ,4092 ,4093 ,4094 ,4094 ,4094 ,4095 ,
4095 ,4095 ,4096 ,4096 ,4096 ,4096 ,4096 ,4096 ,4096 ,4096 ,4096 ,4095 ,4095 ,4095 ,4095 ,4094 ,4094 ,4093 ,
4093 ,4092 ,4092 ,4091 ,4090 ,4089 ,4089 ,4088 ,4087 ,4086 ,4085 ,4084 ,4083 ,4081 ,4080 ,4079 ,
4078 ,4076 ,4075 ,4074 ,4072 ,4071 ,4069 ,4067 ,4066 ,4064 ,4062 ,4060 ,4059 ,4057 ,4055 ,4053 ,
4051 ,4049 ,4047 ,4044 ,4042 ,4040 ,4038 ,4035 ,4033 ,4030 ,4028 ,4025 ,4023 ,4020 ,4017 ,4015 ,
4012 ,4009 ,4006 ,4003 ,4000 ,3997 ,3994 ,3991 ,3988 ,3985 ,3982 ,3978 ,3975 ,3972 ,3968 ,3965 ,
3961 ,3958 ,3954 ,3951 ,3947 ,3943 ,3939 ,3936 ,3932 ,3928 ,3924 ,3920 ,3916 ,3912 ,3908 ,3904 ,
3899 ,3895 ,3891 ,3887 ,3882 ,3878 ,3873 ,3869 ,3864 ,3860 ,3855 ,3850 ,3846 ,3841 ,3836 ,3831 ,
3827 ,3822 ,3817 ,3812 ,3807 ,3802 ,3796 ,3791 ,3786 ,3781 ,3776 ,3770 ,3765 ,3760 ,3754 ,3749 ,
3743 ,3738 ,3732 ,3726 ,3721 ,3715 ,3709 ,3703 ,3698 ,3692 ,3686 ,3680 ,3674 ,3668 ,3662 ,
3656 ,3650 ,3643 ,3637 ,3631 ,3625 ,3618 ,3612 ,3606 ,3599 ,3593 ,3586 ,3580 ,3573 ,3567 ,3560 ,
3553 ,3547 ,3540 ,3533 ,3526 ,3519 ,3513 ,3506 ,3499 ,3492 ,3485 ,3478 ,3471 ,3464 ,3456 ,3449 ,
3442 ,3435 ,3428 ,3420 ,3413 ,3406 ,3398 ,3391 ,3383 ,3376 ,3368 ,3361 ,3353 ,3345 ,3338 ,3330 ,
3322 ,3315 ,3307 ,3299 ,3291 ,3283 ,3276 ,3268 ,3260 ,3252 ,3244 ,3236 ,3228 ,3220 ,3212 ,3203 ,
3195 ,3187 ,3179 ,3171 ,3162 ,3154 ,3146 ,3137 ,3129 ,3121 ,3112 ,3104 ,3095 ,3087 ,3078 ,3070 ,
3061 ,3053 ,3044 ,3035 ,3027 ,3018 ,3009 ,3001 ,2992 ,2983 ,2974 ,2966 ,2957 ,2948 ,2939 ,2930 ,
2921 ,2912 ,2903 ,2894 ,2886 ,2876 ,2867 ,2858 ,2849 ,2840 ,2831 ,2822 ,2813 ,2804 ,2795 ,2785 ,
2776 ,2767 ,2758 ,2748 ,2739 ,2730 ,2721 ,2711 ,2702 ,2693 ,2683 ,2674 ,2664 ,2655 ,2646 ,2636 ,
2627 ,2617 ,2608 ,2598 ,2589 ,2579 ,2570 ,2560 ,2551 ,2541 ,2531 ,2522 ,2512 ,2503 ,2493 ,2483 ,
2474 ,2464 ,2454 ,2445 ,2435 ,2425 ,2416 ,2406 ,2396 ,2387 ,2377 ,2367 ,2357 ,2348 ,2338 ,2328 ,
2318 ,2309 ,2299 ,2289 ,2279 ,2269 ,2260 ,2250 ,2240 ,2230 ,2220 ,2211 ,2201 ,2191 ,2181 ,2171 ,
2161 ,2151 ,2142 ,2132 ,2122 ,2112 ,2102 ,2092 ,2083 ,2073 ,2063 ,2053 ,2043 ,2033 ,2023 ,2013 ,
2004 ,1994 ,1984 ,1974 ,1964 ,1954 ,1945 ,1935 ,1925 ,1915 ,1905 ,1895 ,1885 ,1876 ,1866 ,1856 ,
1846 ,1836 ,1827 ,1817 ,1807 ,1797 ,1787 ,1778 ,1768 ,1758 ,1748 ,1739 ,1729 ,1719 ,1709 ,1700 ,
1690 ,1680 ,1671 ,1661 ,1651 ,1642 ,1632 ,1622 ,1613 ,1603 ,1593 ,1584 ,1574 ,1565 ,1555 ,1545 ,
1536 ,1526 ,1517 ,1507 ,1498 ,1488 ,1479 ,1469 ,1460 ,1450 ,1441 ,1432 ,1422 ,1413 ,1403 ,1394 ,
1385 ,1375 ,1366 ,1357 ,1348 ,1338 ,1329 ,1320 ,1311 ,1301 ,1292 ,1283 ,1274 ,1265 ,1256 ,1247 ,1238 ,
1229 ,1220 ,1211 ,1202 ,1193 ,1184 ,1175 ,1166 ,1157 ,1148 ,1139 ,1130 ,1122 ,1113 ,1104 ,1095 ,
1087 ,1078, 1069 ,1061 ,1052 ,1043 ,1035 ,1026 ,1018 ,1009 ,1001 ,992 ,984 ,975 ,967 ,959 ,
950 ,942 ,934 ,925 ,917 ,909 ,901 ,893 ,884 ,876 ,868 ,860 ,852 ,844 ,836 ,828 ,
820 ,813 ,805 ,797 ,789 ,781 ,774 ,766 ,758 ,751 ,743 ,735 ,728 ,720 ,713 ,705 ,
698 ,690 ,683 ,676 ,668 ,661 ,654 ,647 ,640 ,632 ,625 ,618 ,611 ,604 ,597 ,590 ,
583 ,577 ,570 ,563 ,556 ,549 ,543 ,536 ,529 ,523 ,516 ,510 ,503 ,497 ,490 ,484 ,
478 ,471 ,465 ,459 ,453 ,446 ,440 ,434 ,428 ,422 ,416 ,410 ,404 ,398 ,393 ,387 ,
381 ,375 ,370 ,364 ,358 ,353 ,347 ,342 ,336 ,331 ,326 ,320 ,315 ,310 ,305 ,300 ,
294 ,289 ,284 ,279 ,274 ,269 ,265 ,260 ,255 ,250 ,246 ,241 ,236 ,232 ,227 ,223 ,
218 ,214 ,209 ,205 ,201 ,197 ,192 ,188 ,184 ,180 ,176 ,172 ,168 ,164 ,160 ,157 ,
153 ,149 ,145 ,142 ,138 ,135 ,131 ,128 ,124 ,121 ,118 ,114 ,111 ,108 ,105 ,102 ,
99 ,96 ,93 ,90 ,87 ,84 ,81 ,79 ,76 ,73 ,71 ,68 ,66 ,63 ,61 ,58 ,
56 ,54 ,52 ,49 ,47 ,45 ,43 ,41 ,39 ,37 ,36 ,34 ,32 ,30 ,29 ,27 ,
25 ,24 ,22 ,21 ,20 ,18 ,17 ,16 ,15 ,13 ,12 ,11 ,10 ,9 ,8 ,7 ,
7 ,6 ,5 ,4 ,4 ,3 ,3 ,2 ,2 ,1 ,1 ,1 ,1 ,
0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,
1 ,1 ,1 ,2 ,2 ,2 ,3 ,4 ,4 ,5 ,
6 ,6 ,7 ,8 ,9 ,10,11 ,12 ,13 ,14 ,15 ,16 ,18 ,19 ,20 ,22 ,
23 ,25 ,26 ,28 ,29 ,31 ,33 ,35 ,36 ,38 ,40 ,42 ,44 ,46 ,48 ,51 ,
53 ,55 ,57 ,60 ,62 ,64 ,67 ,69 ,72 ,75 ,77 ,80 ,83 ,86 ,88 ,91 ,
94 ,97 ,100,103, 106,110 ,113 ,116 ,119 ,123 ,126 ,129 ,133 ,136 ,140 ,144 ,
147 ,151 ,155 ,158 ,162 ,166 ,170 ,174 ,178 ,182 ,186 ,190 ,194 ,199 ,203 ,207 ,
212 ,216 ,220 ,225 ,229 ,234 ,239 ,243 ,248 ,253 ,257 ,262 ,267 ,272 ,277 ,282 ,
287 ,292, 297 ,302 ,307 ,313 ,318 ,323 ,328 ,334 ,339 ,345 ,350 ,356 ,361 ,367 ,
372 ,378 ,384 ,390 ,395 ,401 ,407 ,413 ,419 ,425 ,431 ,437 ,443 ,449 ,456 ,462 ,
468 ,474 ,481 ,487 ,493 ,500 ,506 ,513 ,519 ,526 ,533 ,539 ,546 ,553 ,559 ,566 ,
573 ,580 ,587 ,594 ,601 ,608 ,615 ,622 ,629 ,636 ,643 ,650 ,658 ,665 ,672 ,679 ,
687 ,694 ,702 ,709 ,717 ,724 ,732 ,739 ,747 ,754 ,762 ,770 ,777 ,785 ,793 ,801 ,
809 ,816 ,824 ,832 ,840 ,848 ,856 ,864 ,872 ,880 ,888 ,897 ,905 ,913 ,921 ,929 ,
938 ,946 ,954 ,963 ,971 ,979 ,988 ,996 ,1005,101,1022,1030, 1039,1048, 1056,1065,
1073,1082, 1091,1100 ,1108 ,1117 ,1126 ,1135 ,1144 ,1152 ,1161 ,1170 ,1179 ,1188 ,1197 ,1206 ,
1215 ,1224 ,1233 ,1242 ,1251 ,1260 ,1269 ,1279,1288 ,1297 ,1306 ,1315 ,1324 ,1334 ,1343 ,1352 ,
1361 ,1371 ,1380 ,1389 ,1399 ,1408 ,1417 ,1427 ,1436 ,1446 ,1455 ,1465 ,1474 ,1483 ,1493 ,1502 ,
1512 ,1522 ,1531 ,1541 ,1550 ,1560 ,1569 ,1579 ,1588 ,1598 ,1608 ,1617 ,1627 ,1637 ,1646 ,1656 ,
1666 ,1675 ,1685 ,1695 ,1705 ,1714 ,1724 ,1734 ,1743 ,1753 ,1763 ,1773 ,1783 ,1792 ,1802 ,1812 ,
1822 ,1831 ,1841 ,1851 ,1861 ,1871 ,1881 ,1890 ,1900 ,1910 ,1920 ,1930 ,1940 ,1949 ,1959 ,1969 ,
1979 ,1989 ,1999 ,2009 ,2018 ,2028 ,2038
};
uint32_t DualSine12bit[1305];
uint16_t Idx = 0;
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void Delay(__IO uint32_t nCount);
/* Private functions ---------------------------------------------------------*/
/**
  * @brief   Main program.
  * @param  None
  * @retval None
  */
int main(void)
{
  /* System Clocks Configuration */
  RCC_Configuration();  
  /* Once the DAC channel is enabled, the corresponding GPIO pin is automatically
     connected to the DAC converter. In order to avoid parasitic consumption,
     the GPIO pin should be configured in analog */
  GPIO_Configuration();
  /* TIM2 Configuration */
  /* Time base configuration */
  //TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
  TIM_TimeBaseStructure.TIM_Period =1;    
  TIM_TimeBaseStructure.TIM_Prescaler = 1379;    
  TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;    
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
  TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);
  /* TIM2 TRGO selection */
  TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);
  /* DAC channel1 Configuration */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
  DAC_InitStructure.DAC_WaveGeneration =DAC_WaveGeneration_Triangle ;  //DAC_WaveGeneration_None
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;
  DAC_Init(DAC_Channel_1, &DAC_InitStructure);
  /* DAC channel2 Configuration */
//  DAC_Init(DAC_Channel_2, &DAC_InitStructure);  xiaolin

  /* Fill Sine32bit table */
//  for (Idx = 0; Idx < 32; Idx++)  xiaolin
//  for (Idx = 0; Idx < 255; Idx++)
  for (Idx = 0; Idx < 1305; Idx++)
  {
    DualSine12bit[Idx] = (Sine12bit[Idx]

安

其实你不用这么麻烦的，你可以使用sin正弦函数来实现。可能是你的数组的问题。另外，你的DAC输出位数也没配置。

xiaolin88

您说的很对数组有问题,我眼睛都看花了,在同事的帮忙下,才发现.
1>数组中4096改为4095,(用EXECL计算出来,自动4舍5入了,4096溢出了变成了0).
2> 数组中的"...,1005,101,1022,..."中的101改为1010.
3>
将DAC_InitStructure.DAC_WaveGeneration =DAC_WaveGeneration_Triangle ; //有锯齿
改为: DAC_InitStructure.DAC_WaveGeneration =DAC_WaveGeneration_None;
就可以到很光滑的频率为20HZ的正弦波.
您提出DAC输出位数没配置,我确实没有配置,是不是用DMA发送就不用配置呢?谢谢您帮忙!

chinajieli

在百度上面搜索一下就有了！

笑海-404603

楼主，能不能把代码发给我一下啊
我最近也在搞12bit dac输出波形
没搞好，z994051@163.com
感谢！